Assessment of risk of exposure to Campylobacter species and their antibiotic-resistant genes from selected rivers in the Eastern Cape, South Africa

Abstract

Contaminated rivers play a critical role in the transmission of Campylobacter and antibiotic-resistant genes (ARGs) in many parts of the world. South Africa is a water-scarce country which relies on its freshwater systems such as rivers for recreation, irrigation, and domestic activities. This study assesses the potential human exposure to Campylobacter and its ARGs from rivers through the ingestion route in two South African rivers. The concentration of viable Campylobacter and ARGs in selected rivers was determined using quantitative PCR. The concentrations were then used to estimate the number of gene copies a person could ingest after swimming in the contaminated water for 1 h (intake burden). The human intake burden of Campylobacter 16 S rRNA copies per 1-h swimming event ranged from 7.1 × 105–3.7 × 106 copies/h for the Bloukrans River, and 9.9 × 101–2.3 × 105 copies/h for the Swartkops River. The intake burden of Campylobacter ARGs ranged from 1.64 × 104–5.8 × 105 copies/h for cmeB; 1.0 × 103–5.7 × 104 copies/h for tetO for the Bloukrans River, and 3.6 × 102–1.551 × 105 copies/h (cmeB) and 9.98 × 102–5.7 × 104 copies/h (tetO) for the Swartkops River. Ingestion of water from contaminated rivers during recreation, cultural, or religious activities may lead to human exposure to ARGs, posing a health risk. In many communities in the world, rivers play an important role in the social and cultural lives of people, and so it is important to monitor the quality of river water. Studies such as these will help prevent the spread of antibiotic-resistant genes and waterborne diseases caused by pathogens such as Campylobacter.